[MARMAM] Two new papers on South American marine mammals electrocardiography

Diego Rodríguez dhrodri at gmail.com
Thu Jul 14 10:39:03 PDT 2022

Dear MARMAM community,

On behalf of all the co-authors, we are happy to share our recent
publications on electrocardiography in South American pinnipeds and
Burmeister porpoises.

All inquiries and copies of the papers should be directed to Mariela
Dassis (marieladassis at gmail.com).

Thank you!

Diego Rodríguez

Dassis,M., C.de León, A.Díaz, A.Faiella, A.Saubidet, D.Rodríguez,
E.Castro. 2022. First description of the Burmeister porpoise (Phocoena
spinipinnis) electrocardiogram. J Exp Zool A Ecol Integr Physiol.
2022;1–7. DOI: 10.1002/jez.2641.


The aim of this study was to make the first characterization of the
electrocardiogram (ECG) of the Burmeister porpoise (Phocoena
sipinipinnis). A total of three ECGs were made in one, wild juvenile
female (body weight = 32.5 kg, Lt = 1.45 m), temporarily held in
captivity for rehabilitation at Mar del Plata Aquarium (Argentina).
For ECG recordings, the animal was removed from its pool on a
stretcher under constant veterinary supervision. A traditional
six‐lead system in the frontal plane was used, with the typical four
“extremities” electrodes positioned bilaterally. ECGs were readable
and all waves were detectable. The QRS complexes were characterized by
Q wave absence in all leads. The ECG characteristically displayed
distinctly defined STs, with a T wave clearly differentiated from the
QRS complex. An STs elevation was detected in leads II and III. The
mean electrical axis was −79°, meaning a cranial left axis
orientation. The animal showed normal sinus rhythm and heart rate (HR)
showed a continuous oscillation between tachycardia and bradycardia.
Mean HR from all recordings was 147.02 ± 24.95 bpm (range = 71–176, n
= 178). Evidence of the occurrence of respiratory sinus arrhythmia was
detected through HR variations and RR interval differences, which
suggested an adequate cardiovascular system compensation to handling
conditions. This study has reported ECG amplitude and duration
measurements of a potentially healthy specimen, which represents the
starting point for the determination of normal ECG values for this
species. Also, it has confirmed that ECG is a valuable noninvasive
tool for rapid cardiac health assessment in small cetaceans.

Dassis,M., C.de León, A.Díaz, E.Rodríguez, D.Rodríguez, G.Giardino,
E.Castro. 2022. Comparative electrocardiogram in two anesthetized
pinnipeds, the South American fur seal (Arctocephalus australis) and
the Southern sea lion (Otaria byronia), with analysis of ECG
parameters allometry. Mar Mam Sci. 2022;1–15. DOI: 10.1111/mms.12915.


The mammalian heart has been described as a highly evolutionarily
conserved structure and the cardiovascular system allometry has been
fully studied among many mammalian species, but few of these studies
have been focused on marine mammals. Previously reported
electrocardiogram (ECG) of anesthetized Southern sea lions (SSL; n =
13) and South American fur seals (SAFS; n = 19) females were compared,
and linear models were used to examine variations of ECG parameters
with body mass (BM) and heart rate (HR). Electrocardiograms resulted
in qualitatively similar characteristics (rhythm, polarity patterns,
mean electrical axes orientation, and waves/complex forms), but there
were significant quantitative differences in HR and all ECG
parameters. With few exceptions, duration and amplitude parameters
were significantly higher in the SSL, whereas the SAFS had a
significantly higher HR. Allometric scaling was verified for most
duration variables (P, T, QRS, and PR interval) and P wave amplitude,
which were all significantly and positively associated with BM, with
no significant effect found for HR. Results suggest that the cardiac
conduction system is highly conserved, and allometry occurs for these
species even in anesthetized subjects, particularly in atrial
contraction and atrioventricular conduction, which was proposed as
potentially related to optimal atrioventricular activation sequence
and high hemodynamic efficiency.

Dr.Diego Rodríguez
Instituto de Investigaciones Marinas y Costeras,
Facultad de Ciencias Exactas y Naturales,
Universidad Nacional de Mar del Plata-CONICET.
Casilla de Correos 1260 (Correo Central)
(7600) Mar del Plata, Argentina
TE + 54 (0) 223 4754060 (Int.244)
FAX +54 (0) 223 4753150
Skype: diego291162
Facebook: http://www.facebook.com/groups/136323163081610/
Website: https://www.researchgate.net/profile/Diego_Rodriguez16
ORCID ID: https://orcid.org/0000-0002-5080-3739

"Si los pueblos no se ilustran, si no se divulgan sus derechos, si cada
hombre no conoce lo que puede, vale, debe, nuevas ilusiones sucederán a las
antiguas y será tal vez nuestra suerte cambiar de tiranos sin destruir la
tiranía" (Mariano Moreno)

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